Britain’s Ideal: Green Homes

The Beddington Zero Energy Development (BedZED) is a low carbon eco-community in Wallington, south London. Credit
Kieran Doherty/Reuters

LONDON — Aiming to drastically cut its emissions of planet-warming pollutants, Britain is telling its home builders to design a new generation of super-efficient houses that use only clean power and add no net carbon to the atmosphere.

Its rules will mandate that all new homes be zero-carbon by 2016, one of the toughest requirements in the world. While officials and the industry are still working out what exactly that will mean, it is certain to bring big and potentially costly changes to a sector now suffering through a painful slowdown.

Architects, construction companies and manufacturers will have to approach development in a fundamentally new way, thinking from the earliest stages of planning about things like energy efficiency, solar panels and communitywide heat-sharing systems.

The government and environmentalists say this is necessary if the country is to meet the goal, now enshrined in law in the Climate Change Act, of an 80 percent cut in carbon dioxide emissions by 2050.

John W. Alker, a spokesman for the UK Green Building Council, which promotes sustainable construction in Britain, said the government had recognized that this would mean more than just incremental change. “It’s not about saying how do we do what we do now but a little bit better, but saying how do we do the ultimate?” he said.

Although many countries are seeking to reduce emissions from offices and other commercial properties, Britain’s move puts it at the forefront of action on carbon from homes, along with Germany and Scandinavia, where super-efficient “passive houses” are gaining popularity.

Officials here say they are also working on a plan to require new commercial buildings to be zero-carbon by 2019, but have yet to complete those rules.

Commercial structures account for 18 percent of Britain’s carbon emissions, Mr. Alker said. Combined with housing’s share, the energy used in buildings is responsible for 45 percent of the country’s global-warming gases.

The zero-carbon homes effort coincides with plans to encourage the construction of three million houses by 2020 to ease a national shortage. That work is now stalled by the recession, which has sent housing starts plummeting, but homes that have not yet been built are still expected to account for 20 percent of all residences in 2050, according to the Zero Carbon Hub, a public-private body set up to drive implementation of the new standard.

The decision to eliminate newly built homes’ carbon emissions sends an important signal about how seriously Britain takes the environmental challenge, said Simon J. McWhirter, of the conservation group WWF. Still, it is only a first step, advocates warn. Even in a good year, newly built houses are only about 1 percent to 2 percent of the housing stock.

The Department of Energy and Climate Change says it wants existing buildings to be close to zero-carbon by 2050, and has proposed a list of voluntary measures like home energy makeovers. But there are no plans for a compulsory program similar to the one for new homes, disappointing environmentalists and angering some in the construction industry.

The industry worked closely with green groups and government to design the zero-carbon requirement, which was announced in 2006 and will be reached after stepping-stone increases come into force in 2010 and 2013.

It applies only to England, although regional governments in Wales and Scotland are taking similar measures.

John H. Slaughter, policy director of the Home Builders Federation, the main industry body, said builders recognize the importance of carbon reductions and are prepared to meet the new standards: but without a requirement to retrofit existing homes, the 2016 mandate could put new home developers at an unfair disadvantage, he said.

A zero-carbon home could cost £20,000, or $32,000, more to build than a traditional one — a price buyers may not be willing to pay.

“Consumers do have a choice,” Mr. Slaughter said. “They don’t have to buy a new home, they can buy an existing home.”

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Others say zero-carbon won’t be that expensive. Ewan Willars, head of policy for the Royal Institute of British Architects, said much of the technology used for at-home renewable power generation is manufactured only on a small scale, and will get much more economical as suppliers begin to produce for a mass market.

Sue E. Riddlestone, executive director of BioRegional, an environmental group that built BedZED, a 100-unit zero energy housing complex in south London, in 2002, said that neighborhood-based energy generation would not have to be developers’ responsibility, but could be spun off to power companies that would turn a profit after investing in equipment. Others have proposed novel financing mechanisms or long-term loans to spread the cost over time, when it could be balanced by savings on energy bills.

“The front-end cost is probably the single biggest barrier” to achieving a breakthrough in building standards, Mr. Slaughter said. “That’s part of the conversation we’re having with government.”

Also worrying home builders and the companies that supply them is a lack of agreement on the definition of zero-carbon. After early ideas proved unworkable, officials are reconsidering their initial plans, and say they will announce new parameters by late July.

A zero-carbon home is one in which energy use has been reduced as much as possible and which gets the power it does need only from clean sources. If it takes some energy from the national grid, it must replace it by feeding power in over the course of the same year.

It is the details that have proven tricky. Government’s initial hope, that every zero-carbon home or development would generate all its renewable power on-site, would be impossible for about 80 percent of projects, said Neil Jefferson, chief executive of the Zero Carbon Hub.

Mr. Jefferson said the new definition is likely to set out priorities, requiring builders first to ensure that a new home is as energy-efficient as possible, meeting a power-saving target still to be announced. Then, they will have to install as much home- or development-based energy generation as possible, tapping sources like solar water heating and wind power.

Finally, they will probably be allowed to provide some energy from off-site renewable sources, maybe even paying to erect a new turbine at a wind farm hundreds of miles away. Environmentalists and builders are waiting to see which options the government deems acceptable.

What is possible varies widely from site to site. An apartment building in central London, for example, has far less space for wind turbines and solar panels than a rural farmhouse, but may be more easily able to pipe heat from a nearby biomass boiler to many homes.

Architects and builders say they will have to think about sustainability from the start. Maximizing roof space and orienting buildings toward the south or southwest, for example, mean that even if photovoltaic cells are not installed immediately, a home will be able to accommodate them as they grow less costly and more sophisticated in the future, said Mr. Willars, of the architects’ institute.

For most homes, a solar panel on the roof can provide about 60 percent of all hot water needed, Mr. Jefferson said. Energy-efficient boilers and appliances cut power use. District heating, where heat created from renewable sources like biomass or as an otherwise-wasted byproduct of electricity generation is distributed to numerous residences, uses less energy than traditional heating. And top-quality building materials and modern construction methods can drastically reduce the energy lost from a home, said Alan Shingler, a partner at the London architecture firm Sheppard Robson, which designed the Lighthouse, a zero-carbon home in Watford, outside London.

Solutions linking the power needs of whole neighborhoods work better than looking at one home in isolation, Mr. Willars said. “The days when we were striving to achieve an airtight box bristling with wind turbines are disappearing,” he said. “Now we’re trying to get to zero carbon in the most efficient, most effective manner.”

While a handful of model zero-carbon developments already exist, building such homes on a wide scale is a completely new challenge for the industry.

Mr. Slaughter, of the Homebuilders Federation, said construction workers would likely need training in new construction methods. Suppliers of everything from solar panels to insulation and draft-excluding windows would have to step up production for the 2016 target to be achievable, he added.

While building standards have risen sharply in recent years, delivering hundreds of thousands of zero-carbon homes a year would be tough, said Simon Storer, spokesman for the Construction Products Association, a trade group based in London.